This invention relates to a method of repairing cracks in concrete structures such as precast or cast in place flooring, walls, beams, or the like, or generally any formed concrete for structural strength and to prevent leakage. The invention also relates to a port and plug assembly for use in the method.
Various methods have been used for repairing such cracks, but the one previously known to applicants and believed to be the most effective, involved the use of epoxies to seal the surface of the crack and to inject into the crack cavity behind the surface seal through port assemblies. Heretofore, the port assemblies each had a hollow shaft portion with an enlarged frustoconical portion at one end thereof. A series of holes were drilled at spaced locations along the crack to be sealed, and the frustoconical ends of the port assemblies were inserted in the drilled holes. An epoxy surface seal was then applied partially into the crack and into the holes over the frustoconical ends of the port assemblies. The surface area of the concrete structure adjacent the crack was also covered with the surface seal, so that after curing, the surface seal acted to hold the port assemblies in place and as a surface barrier for an epoxy filler. After the surface seal had cured, the epoxy filler was injected through the ports and into the crack cavity behind the surface seal for structural strength and to effectively seal the crack against leakage. Generally, the technique was to first inject filler through one port until the filler appeared at the next port, whereupon the first port was plugged and filler was injected into the next port, and so on until the entire crack cavity was filled and all of the ports were plugged.
The present invention represents an improvement over this method and port assembly. While the previous method was very effective in sealing cracks, it was relatively labor intensive as compared with the method of the present invention in that it required the drilling of holes along the crack, along with additional related drilling, coring, and vacuuming equipment. As the method is used primarily with concrete structures, the drilling of the holes was time consuming and often tedious. The holes had to be accurately placed over the crack and had to be sized to receive the frustoconical end of the port assemblies. For example, on an eight inch (20.32 cm) thick, eight foot (243.8 cm) high wall with a crack extending the full height, the holes might typically be placed about eight inches ((20.32 cm) apart, requiring the drilling of twelve such holes. Furthermore, concrete dust from the drilling often clogged the crack and had to be removed requiring additional time and equipment. The problem is multiplied where there are multiple cracks.
The present invention eliminates the problem of the prior method. The port and plug assembly of the present invention, rather than having a frustoconical portion, has a generally flat flange at one end of the hollow shaft which is embedded in the surface seal at a location over the crack and generally adjacent the outer surface of the structure to which the surface seal is applied. The flat configuration of the flange allows for a smooth application of the surface seal over the flange so as to embed substantially the entire flange in the surface seal where it becomes thoroughly captured and sealed therein when the surface seal cures. Thus, the surface seal itself acts to capture and hold the port assemblies, as well as sealing the outer surface of the crack, without the need for the labor intensive and tedious drilling of holes in the concrete structure which weaken the structure. The present invention virtually eliminates the need for expensive pumps and related drilling and vacuuming equipment.
In accordance with the method of the present invention, rods are inserted into the crack at the location where the holes of the prior method would have been placed. The rods act to properly locate the port assemblies which are to be placed thereover. After the rods are in place, the surface seal is applied partially into the crack opening near the wall surface from which the rods extend, around the rods themselves, and onto the wall surface adjacent the crack. The port and plug assemblies with plugs removed are placed over the rods and the relatively flat flanges of the port assemblies are embedded and covered substantially in their entirety into the surface seal. The surface seal is allowed to cure and the rods are removed so that each port assembly communicates with the crack cavity behind the seal. After the surface seal cures, epoxy filler is injected into the port assemblies, using safe low pressure hand held tools, and the port assemblies plugged as with the prior method. By the use of the rods, the port assemblies are accurately placed over the crack for ease in injecting the filler, and no drilling is required to locate the ports.
Thus, it is a primary object of the present invention to provide a method of repairing cracks in structures, primarily concrete structures, and a port and plug assembly for use therewith, which is not only effective in repairing such cracks, but which is relatively easy, less time consuming, and which provides for accurate placement of the port assemblies, and with no loss in structural strength or decrease in structural integrity, for injection of the filler and substantially thorough and complete sealing of the crack.
This and other objects of the invention are apparent from the drawing and detailed description to follow.